The present invention relates to an ink-jet head assembling apparatus for assembling a head nozzle of a printing head for discharging an ink by mounting a top plate member formed with nozzles corresponding to a plurality of heaters on a heater board formed with the heaters.
In recent years, a printing head of so-called bubble-jet type, which heats an ink to form bubbles when an ink is discharged to be printed on a paper sheet, has been developed, and put into practical applications since it is advantageous for improving printing precision.
In an assembling apparatus for assembling a bubble-jet type printing head, heaters for heating an ink, and discharge orifices for discharging bubbles, formed by heating and boiling the ink using the heaters toward, a paper sheet must be precisely aligned on the order of microns. For example, in order to attain printing precision as high as about 360 dpi (dots per inch), 64 discharge orifices must be aligned at a constant pitch within a range of about 4.5 mm, and the aligning pitch in this case is as small as about 70 microns.
Upon formation of discharge orifices at such a very small pitch, the discharge orifices can be formed with allowable predetermined high precision in an orifice plate to be attached to the front surface of a top plate member by using, e.g., an ultra-high-precision process machine such as a laser process machine. On the other hand, upon formation of heaters, the heaters can be similarly formed on a heater board with allowable predetermined high precision by using an ultra-high-precision etching technique.
However, in a conventional assembling apparatus, a heater board and a top plate are respectively set using special-purpose jigs so as to align them, so that the top plate can be placed on the heater board while the axes of heaters on the heater board and discharge orifices formed in the orifice plate precisely coincide with each other. Thereafter, the heater board and the top plate are manually aligned while alternately observing the heaters and orifices using a metal microscope.
In an adhering operation of the heater board and the top plate after alignment, an ultraviolet-setting adhesive is manually applied, the heater board and the top plate are manually pressed against each other, and ultraviolet rays are radiated on the adhesive at the start timing of adhesion, thereby setting the adhesive.
In this manner, such manual alignment results in variations among workers. For example, variations depending on a degree of skill of each worker, and a variation depending on a degree of fatigue of each worker often result. These variations impair position adjustment precision, and pose a problem in reliability of final products. In addition, since visual measurements and manual operations of jigs are repeated, a time required for alignment is prolonged, resulting in a decrease in assembling efficiency caused by a prolonged assembling time. Furthermore, much time is required to train workers until the workers are sufficiently skilled for these tasks.
Workers suffer from eye strain caused by visual measurements over a long period of time, and ultraviolet radiation.
Furthermore, since an adhering operation is manually executed, a worker must hold the two members in a joined state until the adhesive is set, and the relative position between the members may be shifted during holding.
Since a worker must hold the two members over a long period of time, he or she is fatigued considerably, and demand has arisen for improvement of work conditions. In order to shorten an adhesion time, an instantaneous adhesive may be used. However, when an instantaneous adhesive is used, an adhesion force works immediately after the adhesive is applied. For this reason, it is difficult to align the two members while the adhesive is interposed therebetween. In addition, since fine powdery impurities are mixed in a gas of the instantaneous adhesive, the impurities may clogg the finely processed discharge orifices. For these reasons, the instantaneous adhesive cannot be used.
Since ultraviolet rays are employed to set an adhesive, workers must directly see ultraviolet rays in each adhesion process, thus posing a problem of eye strain of workers.